The use of plastics or other containers having a metallic foil or other membrane closure sealed to the neck thereof is commonplace; such containers are used for materials as diverse as milk and industrial chemicals. However, the removal or other treatment of the seal to gain access to the contents is difficult and presents particular problems when the contents are liquid and hazardous, in that splashes are likely to occur or the operative's fingers are likely to come in contact with the contents. Such containers are commonly used for the packaging of concentrated agricultural chemical solutions intended for spraying. To prepare the solution for spraying, the operative will need to open one or more containers and discharge part or all of the contents to a feed tank in which the chemical is diluted to the required spraying concentration. The operative will generally wish to keep the initial addition and mixing time and subsequent replenishment times to a minimum for economic reasons, but this militates against the use of recommended safety procedures and increases the risks of spillage, splashing or the increase of other potentially hazardous exposures. These risks are present despite the use of protective clothing and may be exacerbated in windy conditions.